Thermal Actuation of Riblets for Drag Control
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Solution Overview
Problem
Aircraft riblets, used to reduce drag and improve aerodynamic efficiency, are prone to damage and contamination by foreign particles, leading to increased maintenance costs and reduced performance.
Innovation Solution
Integration of thermal expansion elements, particularly negative thermal expansion materials, within or adjacent to riblet structures that alter their shape in response to temperature changes, allowing for controlled displacement and protection from damage and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If riblets are used to reduce drag and improve aerodynamic efficiency, then aerodynamic performance is improved, but the riblets are prone to damage and contamination by foreign particles
Solution Approach 1:
The riblet structure transitions from a static configuration to a dynamic one that can change its state based on operational conditions. The riblets can be deployed when aerodynamic performance is needed and retracted when protection from damage or contamination is required, allowing the system to adapt between performance and reliability states
Solution Approach 2:
The invention changes the physical state or configuration parameter of the riblets through thermal actuation. By using materials that expand or contract with temperature changes, the riblets can be actuated to deploy or retract without complex mechanical systems, enabling transition between exposed and protected states
2Device complexity
If thermal expansion elements are integrated within riblet structures to enable thermal actuation, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The thermal expansion element is integrated within or operatively coupled to the riblet structure, merging the actuation function with the riblet structure itself. This consolidation eliminates separate actuation mechanisms and reduces overall device complexity while the embedded design allows for standardized manufacturing processes
Solution Approach 2:
Complex mechanical actuation systems (motors, linkages, sensors) are replaced with a passive thermal expansion mechanism. The riblets respond automatically to temperature changes through the thermal expansion properties of embedded materials, eliminating the need for active mechanical control systems
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables the riblets to adjust their aerodynamic characteristics without complex mechanical actuation, reducing maintenance costs and improving efficiency by avoiding damage and particle trapping, while allowing for adaptive control of drag coefficients based on flight conditions.
Implementation Method 1
The thermal expansion element includes a negative thermal expansion material
Data Source
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AI summary
Thermal actuation of a riblet is described herein. An apparatus includes a riblet structure (300) defining an aerodynamic surface (303) of a vehicle. The apparatus also includes a thermal expansion element (304) within or operatively coupled to the riblet structure (300), wherein the thermal expansion element (304) changes shape in response to a surrounding temperature, to displace a movable portion (402) of the riblet structure (300), relative to the aerodynamic surface (303), to alter an aerodynamic characteristic of the vehicle.